1. Field of the Invention
The device relates to a magnetic recording system such as a floppy disk drive system, and more particularly, to a front structure for a downsized magnetic recording system.
2. Related Art
In general, the front of a conventional magnetic recording system using a cartridge type magnetic medium such as a floppy disk, e.g., the front of a 3.5" floppy disk drive system is designed as shown in FIGS. 5 and 6. A front frame C made of a resin and having a disk insertion opening B in a central portion thereof is secured to a front portion a.sub.1 of a shallow U-shaped main chassis A. The front frame C is rigidly secured to the main chassis A by hooking clips c.sub.1 molded integrally on both sides of the back of the front frame C to corresponding hooking holes a.sub.4 arranged on both lateral walls a.sub.2, a.sub.3 of the main chassis A and fitting the front portion a.sub.1 of the main chassis A into both lateral side portions c.sub.2, c.sub.3 and a lower side portion c.sub.4 of the front frame C.
Shaft support portions c.sub.6 into which pivot pins d.sub.1 of a front door D can be press-fitted are molded integrally on both sides of the back of an upper side portion c.sub.5 of the front frame C, the front door D serving to close the disk insertion opening B. Therefore, the front door D is held closed at all times by return springs E set on the shaft support portions c.sub.6. A floppy disk X can be inserted into a disk holder F located in the depth of the disk insertion opening B by forcibly opening the front door D with the floppy disk X.
A light emitting diode (LED) G for indicating operating conditions of the drive system and an eject button H are arranged on the lower side portion c.sub.4 of the front frame C. The eject button H passes through a button hole c.sub.6 arranged on the lower side portion c.sub.4.
There exists a persistent demand for downsizing the thus constructed 3.5" floppy disk drive system so that the drive system can be built in a portable word processor and a personal computer which are required to be smaller and lighter. What imposes a problem in downsizing the front of the drive system is the design of the horizontal dimension W.sub.1, the vertical dimension H.sub.1, and the depth L.sub.1. To reduce the vertical dimension H.sub.1 of the drive system out of these dimensions W.sub.1, H.sub.1, L.sub.1, the following problems must be overcome.
That is, even if the horizontal dimension W.sub.1 and the vertical dimension H.sub.1 of the drive system are managed to be reduced for downsizing purposes, the sectional areas, i.e., the second moments of area of the upper side portion c.sub.5, both lateral side portions c.sub.2, c.sub.3, and the lower side portion c.sub.4 are also reduced, with a particular reduction in the mechanical strength of the upper side portion c.sub.5. As a result, the problem of deformation or breakage of the upper side portion due to external force must be considered. In other words, since the lower side portion c.sub.4 and both lateral side portions c.sub.2, c.sub.3 are secured to the highly rigid main chassis A while fitted into the front portion a.sub.1 of the main chassis A, reduction in the thicknesses thereof is not considered a great problem. However, the horizontally thin and long upper side portion c.sub.5 is secured to both lateral side portions c.sub.2, c.sub.3 only at both ends thereof, and this may impose a problem of deformation or shearing fracture thereof due to reduction in the second moment of area.
Further, the conventional front door D, whose vertical dimension h.sub.1 is large compared with the size of the disk insertion opening B, requires an adequate opening stroke. Therefore, the opening stroke in the depth direction becomes an obstacle for reducing the depth L.sub.1.
Still further, the button hole c.sub.6 for allowing the eject button H to pass therethrough is formed on the lower side portion c.sub.4 of the front frame C, which becomes an obstacle for reducing the vertical dimension H.sub.1 of the front frame C. That is, while the button holes c.sub.6 are formed on the upper side portion c.sub.5 and the lower side portion c.sub.4 of the front frame C, even if the thicknesses of these holes are reduced by managing to reduce the vertical dimensions of the upper side portion c.sub.5 and the lower side portion c.sub.4, the mechanical strength of the portions surrounding the button holes c.sub.6 is reduced. As a result, the front frame C is subjected to cracks and deformation due to secular change.
In addition, the operation of assembling the front frame C and the eject button H is such that the eject button H is positioned in the rear of the front frame C and then the eject button H is inserted into the corresponding button hole c.sub.6 by advancing the eject button H toward the front frame C. Such assembling operation complicates the process of assembling the drive system.
Still further, since the shaft support portions c.sub.6 are molded integrally on the back of the front frame C in order to mount the front door D, it is difficult to shorten the depth L.sub.1.
In addition, since the shaft support portions c.sub.6 are molded integrally on both lateral side portions c.sub.2, c.sub.3 of the front frame C, the horizontal dimension W.sub.1 of the drive system cannot be reduced by reducing the thicknesses of both lateral side portions c.sub.2, c.sub.3.